Ask HN: Do architects play a role in scrum?

I'm currently in a "scrum" team where the whole architecture of the application is thought out by a team of architects, documented in a 40 page document in very much detail (even detailing all the names and settings of all the resources). This all took 3 months to think about and write down. Now that that part is done, the resources are all provisioned by IT and it is now my task as an engineer to "hook things up together". We do this in a "scrum" way, but actually it is already precisely known up-front what will happen in what sprint and all the requirements are already set in stone.

I have some questions about this: what is the role of an architect in an agile process? What we are doing here does NOT at all seem agile to me, it's just waterfall in a scrum jacket. Wouldn't it make more sense to have an architect as part of the team an iteratively let them design stuff?

And are architects still a thing anyway? As an engineer I have boots-on-the-ground experience setting things up, I have all the certifications and knowledge for determining the right way to set this up. Shouldn't a senior engineer being trusted with this rather than a non-coder?

Last question: is it normal to write 40-page documents with all the architecture details before you start building? I never encountered this before at any companies (mind you, this is not a government institution, it's a for-profit company).

To give context: the team exists of only 1 engineer (me), a team of architects that are all working part-time on it, a bunch of stakeholders, product owner, scrum master, external parties. It's a project that should take maybe half a year to build.